2 Fluid Resuscitation

Why fluid resuscitation is needed

Fluid resuscitation replaces fluid lost from the circulation after a major burn. Too little fluid can impair organ perfusion, while too much can worsen tissue and lung edema. Formula-based volumes are starting estimates, not fixed prescriptions; adjust the infusion to the patient’s response.

Choosing an initial fluid estimate

For adults with burns involving $20\%$ or more of total body surface area (TBSA), the described American Burn Association guidance recommends beginning with an estimate of $2\ \text{mL} \times \text{body weight (kg)} \times \%\text{TBSA}$ for the first $24$ hours. Count partial- and full-thickness burns when estimating TBSA, but do not count superficial burns.

The traditional Parkland formula uses $4\ \text{mL} \times \text{body weight (kg)} \times \%\text{TBSA}$. Because protocols and educational materials may specify different formulas, use the formula named in the question or local protocol. Do not substitute one formula for another without stating the change.

Calculating volume and timing

Calculate the starting $24$-hour volume using the specified formula. For the $2\ \text{mL}$ estimate, give half during the first $8$ hours from the time of injury and the other half over the following $16$ hours.

When determining the initial rate, subtract time already elapsed since injury and account for fluid already given. Use the ordered fluid and titration instructions in the applicable burn-center protocol; lactated Ringer’s is commonly used.

Applying the estimate

An adult with a $22\%$ TBSA partial-thickness burn meets the usual adult threshold for formal burn-shock fluid resuscitation, even when no shock is documented. Begin assessment and resuscitation using the applicable protocol; the estimate does not replace clinical reassessment.

For a $70$-kg adult with a $25\%$ TBSA burn, using the $2\ \text{mL}$ estimate:

Half of the starting volume, $1{,}750\ \text{mL}$, is assigned to the first $8$ hours after injury. If the burn occurred $2$ hours ago and no IV fluid has been given, deliver that portion over the remaining $6$ hours:

This is a calculated starting rate, not a rate to continue without reassessment.

Monitoring urine output

A common adult urine-output target is about $0.5\ \text{mL/kg/hour}$. For a $70$-kg adult, that is about $35\ \text{mL/hour}$. An output of $20\ \text{mL}$ in the last hour is below target.

Check the measurement and catheter for obstruction, reassess perfusion and vital signs, review fluids already delivered, and titrate according to the burn protocol. Notify the responsible clinician if output remains low or the patient is deteriorating; do not rely on the formula alone.

Responding to changing condition

If urine output rises well above target after an infusion-rate increase and the patient develops increasing edema, do not simply continue the calculated rate. Reassess promptly and adjust the rate according to clinical response and the burn protocol. High output together with increasing edema can signal that the current rate needs review.

Continue close monitoring of urine output, vital signs, perfusion, respiratory status, and cumulative fluid received. Seek burn-specialist input when needed.